For centuries, it was known that people who survived smallpox became immune to it. For that reason, nearly every culture tried to induce immunity in healthy individuals. The Chinese used tubes to insert powdered smallpox scabs into their nostrils. In Turkey, pus from lesions was scratched into the skin.
Climate graph San Francisco. The driest month is July. There is 1 mm of precipitation in July. Most precipitation falls in January, with an average of 115 mm. Temperature graph San Francisco. With an average of 17.6 Â°C, September is the warmest month. In January, the average temperature is 10.4 Â°C. It is the lowest average temperature of the whole year. San Francisco Climate table // historical Weather data
San Francisco in March. San Francisco weather in March is pretty cold, especially at night time, with temperatures of 9.3Â° and 26.1Â° degrees, so don't forget to pack warm clothes with you. As there are on average 7 rainy days in San Francisco in March chances for rain are low but possible.